Process for the sulphation of ethylene and the sulphation of alpha mixture of ethylene and propylene



Ill

Patented Nov. 1, 1932.

UNITED STATES PATENT OFFICE BENJAMIN 13.330038, OF 6103, GONNECTICU '1, ASSIGNOB TO PETROLEUM CHEKICAL CORPORATION, A CORPORATION 01 DELAWARE PROCESS FOR THE SULIHA'IION OI ETHYLEQIE AND THE SULPHATION 01' A MIXTURE OF ETHYLENE AND PBOPYLEN E v No Drawing.

This invention relates to the sulphation of ethylene or to the sulphation of a mixture of ethylene and propylene, and will be fully understood from the following description:

The ethylene to be sulphated may be obtained from any of thevarious sources from which ethylene is susceptible-of commerc al production either alone or in admixture with other hydrocarbons. The ethylene may, for exam le, be obtained from the destructive distillat on of materials containin carbon and hydrogen, as for example in co ing of coal, or may result from the cracking of natural gas, shale oil or petroleum oil. I

The sulphation of ethylene, either alone or in admixture with other hydrocarbons, has been carried'out b contactin the ethylene in gas phase with sulphuric aci either fuming, anhydrous, or containing minor percentages of water. The sulphation has heretofore been carried out either at atmospheric pressure or at pressures below those hereinafter described, with the simultaneous application of acid concentration and temperature suflicient to maintain commercial reaction velocities. I

have found that under the conditions heretofore employed, a substantial amount of the ethylene is degraded to polymers; and where satisfactory reaction .velocities are obtained, there are ordinarily certain undesired complications, such as charrin and reduction of the acid, polymerization o the hydrocarbon material to tars and heavy oils, etc.

By carrying out the reaction at hi her pressure than heretofore contemplated, am enabled to operate at lower acid concentrations and/or temperatures than have heretofore been applled in combination, and am thereb enabled not only to substantiall 'reduce t e undesirable complications herembefore mentioned, but also to effect substantial economies in the cost of reconcentrating the sulphuric acid employed. By the application of these pressures, I am also enabled to satisfactorily operate with gases containing rela- Applicatlon filed Augult 8, 1980. Serial No. 474,802.

-sha e oil or petroleum oil after olefines of more than 2 carbon atoms have been separated by chemical absorption, c. f., with aqueous sulphuric acid, or by selective physical absorption accomplished by contact with a hydrocarbon oil under pressure. Alternatively,

the ethylene may be produced by rectification from the mixture of olefines produced by cracking shale or petroleum oils. The ethylene or ethylene containing as may also be produced by a combination 0 theforegoing treatments or by any other suitable method.

In the manufacture of gasoline, for example, bycracking petroleum oils the products of cracking are ordinarily fractionated to separate therefrom gasoline and compounds of higher boiling point leaving a residue of normally gaseous hydrocarbons. This resi due may be subjected to oil absorption under pressure to remove hydrocarbons of 4 or more carbon atoms leaving a residue consisting predominantly of hydrocarbons of 3 or less than '3 carbon atoms. This residue may be subjected to chemical treatment to remove the last traces of olefines of more than 2 carbon atoms leaving a mixture of hydrocarbons containing olefines of 2 carbon atoms which is suitable to my purpose. Such a mixture is preferably derived from the products of vapor phase cracking of such oils,

' acid should not exceed 95%,

carried out, for example, at temperatures be-.

tween 1050 and 1100 F. j

The ethylene containing mixture is sulphated by contacting it with aqueous sulphuric acid under pressures in excess of 250 pounds to the square. inch. The sulphuric I-LSO. content, and the temperature should be maintained at the oint at which sulphation takes place active y. I may operate with acid of from 80 to 95%, H 80. content, and at temperatures of from 30 to 125 0. Any pressure in excess of 250 pounds to the square inch may be maintained, inasmuch as the reaction is carried out in the gas phase and the temperature may be maintained above the critical temperature of ethylene.

For practical purposes, I prefer to employ a pressure in excess of 500 pounds. This may, for example, be combined with an acid concentration of from 90 to 95%, H SO, content, and a temperature of from 65 to 85 C.

' v A temperature of 75 C. has been found quite satisfactory within this range of acid concentrations.

When operating under pressures which are adjacent the lower limit hereinbefore specified, I have obtained satisfactory reaction velocities with acid ranging from 80 to 95% at temperatures ranging from 30 to 125 C. Temperature and acid concentration are to an extent reciprocal, and for any fixed pressure and reaction velocity a lower temperature is in equilibrium with a higher acid concentration and a higher tem rature with a lower acid concentration. I ave, for example, obtained satisfactory reaction velocities with acid of from 90 to 95% at temperatures ranging from 30 to 95 C. Similar results have-been obtained with acid of from 85 to 90%, H SO content, at temperatures ranging from 30 to 100 C., and similar results have been obtained with acid of from to I-LSO, content, at temperatures ranging from 30 to 125 C. When operating under pressures which are adjacent the lower limit specified, rapid reaction velocities have been obtained with acid of from to H SO content, at temperatures of from 65 to 85 0., with acid of from 85 to 90%, H 80 content, at temperatures between 80 and C., and with acid of from 80 to 85%, H 80 content, at temperatures between 100 and 125 C.

By the employment of still higher pressures lower acid concentrations and temperatures may be employed in equilibrium with the practical elimination of polymerization. A pressure in excess of 500 pounds per square inch is for this reason highly advantageous, and by the application of pressures in excess of 500 pounds vigorous reaction velocities are obtainable with acidof from 80 to,90%, H S O content, at temperatures between 30 and 50 C. The application of still higher pressures in excess of 1000 pounds per square web, for example, is of further advantage, inasmuch as it results in a corresponding increase of reaction rate without any substantial increase in the amount of polymerization; whereas, if the same reaction rate were obtained by increasing either the temperature or acid concentration at pressures below those herein specified, a marked polymerization loss would ensue. The ap lication of pressures in excess of 1000 poun s per square inch is of further advantage, particularly where dialkyl sulphates are to be manufactured as hereinafter described.

The conditions heretofore employed for the sulphation of ethylene have included such arange of temperature and acid concentration as would have destroyed a substantial proportion of any propylene, if present, with the consequent loss of the propylene and with the simultaneous loss of a proportion' of the ethylene in consequence of the formaene and propylene, I prefer to operate with a sul huric acid containing not exceeding 90%, H 0 content, preferably of 80 to 90%, employing a temperature at which sulphation of the ethylene proceeds actively. A satisfactory temperature for this purpose is from 30 to 50 C. For maximum reaction velocities pressures in excess of 500 pounds per square inch may be employed when sulphating such 'a mixture of ethylene and propylene.

The sulphation reaction is preferably carried out in a column of the bubble tower type,

preferably equipped with plates, bell-caps and down flow pipes, so as to maintaln continuous counter-current contact of the gas and acid. I find that the bubble tower type of cont-actor is highly preferable to the packed tower, inasmuch as it permits the maintenance of a definite volume of acid in the tower at all times and thereby enables me to maintain any desired rate of flow of acid and gas while simultaneously permitting complete control of the time during which the materials are in contact.

It is a further advantage of my invention that by maintaining the range of conditions hereinbefore described I may either produce the mono-alkyl sulphate or may, if desired, by simply holding the acid and gas in contact for a sufficient length of time convert the same either largely or preponderantly, as desired, into the dialkyl sulphate.

When operating-to produce the dialkyl sulpliate it is essential that'the sulphuric acid present in less quantity than is theoretically required for the formation of mono-alkyl sulphates, viz there should be less than one mol of acid tor each mol of ethylene contactedv therewith. For the maximum possible conversion into dialkyl sulphates there should be approximately two mols of ethylene for each mol ofacid. Either the mono or-dialkvl sulphate may be easily hydrolyzed to produce the alcohol therefrom; and inasmuch as one mol. of the dialkyl sulphate yields two mols of alcohol, the acid consumption is sharply reduced in direct proportion to the amount of dialkyl sulphatenerated. When operatin with a mixture 0 ethylene and propylene t ere may be roduced a mixture of simple and mixed dialkyl sulphates],

depending upon which olefine is in excess. am therefore enabled in a single state of treatment by contacting a mixture of ethylene and propcylenewith aqueoussulphuric acid' to procee directly to the formation of mixed alkyl sulphates. The term mixed alkyl sulphates as herein employed, shall denote alk l sulphates containing in combination difi erent alkyl radicals; and the term simple dialkyl sulphates shalldenote dialkyl sulphates containing in combination only one ty e of alkyl radical.

Vhen operating to make the mixed d1- alkyl sul hates, it is of course essential that the acid e present in less quantity than is theoretically necessary to .the formation of mono-alkyl sulphates, vi'z, there should be less than one mol of acid for each unit mol fraction of ethylene and propylene contacted therewith. For maximum production of dialkyl sulphates there should be approximately one mol of acid for each unit mol fraction of ethylene and propylene contacted therewith. If the mixed olefines are not present 1 n equimolar proportions, the olefine which 1s present in excess will to that extent form the corresponding simple dialkyl sulphate. Where the formation of either the simple or mixed dialkyl sulphate is desired, the acld and olefine material will ordinarily be held in contact until the acid has been predominantly converted into dialkyl sulphates. This result is expedited by the application of pressures in excess of 500 pounds per square inch,.and by the application of pressures in excess of 1,000 pounds per square inch the acid may be converted almost entirely into dialkyl sulphates, even when employing acid of relatively low concentration containing, for example, from to By operating within the range of temperatures and acid concentrations hereinbefore disclosed, and by a slight relative elevation of temperature, I find it possible to simul-- taneously generate a mixture of alkyl sulphate and alkyl ether. By the application -ress of the sulphation reaction. The

of pressure within specified, this may be accom lished with much lower concentrations of acids than would otherwise be required, thereby eliminating the undesired side reactions and concomitant production of lymers, tars, etc; which would be inevitab l tlons heretofore employed. The conditions may be so chosen that the ether vagorizes out of the acid liquor and is conducte away and condensed simultaneously with the P ether may also be recovered by absor tion in a hydrocarbon oil, either under tie operating pressure or under 1 hi her pressure. The exact vapor pressure 0 the ether required for this purpose will depend upon the volume of diluent gas resent, and for that reason must be selected with a view to the particular reaction mixture undergoing treatment. I have obtained satisfactory results for the simultaneous generation of ethyl sulphate and ethyl ether by operating with an acid concentration of from 90 to H 80 content, and at a temperature within the range of to 130 C., while maintaining a pressure in excess of 250 pounds to the square inch and preferably in excess of 500 pounds The term sulphation as employed in the description and claims shall denote the treatment with aqueous sulphuric acid resulting in the formation of either mono or dialkyl sulphates.

comprises contacting ethylene 1n gas phase with aqueous sulphuric acid of from 80 to 95%, H SO content, under a pressure in excess of 250 pounds per square inch, said acid .being present in less quantity than is theoretically required for the formation of mono-ethyl sulphate and at a temperature of from 30 to 125 (3., and holding the materials in contact until the acid is converted at least in part into diethyl sulphate.

3. Process of sulphating ethylene, which comprises contacting ethylene in gas phase with aqueous sulphuric acid of from 80 to 95%, H SO content, under a pressure in excess of 500 pounds per square inch and at a temperature of from 30 to 125 C.

4. Process of sulphating ethylene, which comprises contacting ethylenein gas phase the heretofore e under the condiiwith aqueous sulphuric acid of from 80 to' H SO, content, under a pressure 111' excess of 500 pounds 'per square inch, said -acid being present in less quantity than 1s theoretically required for the formation of mono-ethyl sulphate and at a temperature of from 30 to 125 0., and holding the materials in contact until the acid is converted at least in part into diethyl sulphate.

5. Process of simultaneously sulphating ethylene and ropylene, which comprises contacting a mixture of ethylene and propylene with a ueous sulphuric acid of from $0 to 90%, H 0, content, under a pressure 1n excess of 250 pounds per square inch at a temperature of from 30 to 50C.

6. Process of simultaneously sulphating ethylene and propylene, which comprises contacting a mixture of ethylene and propylene with aqueous sulphuric acid of from 80 to 90%, H SO, content, under a pressure in excess of 250 pounds per square inch, said acid being present in less quantity than is theoretically required for the formation of mono-alkyl sulphates at a temperature of from 30 to 50 C., and holding the materials in contact until the acid is converted at least in part into dialykyl sulphates.

7. Process of sulphating ethylene, which comprises contacting ethylene in gas phase with aqueous sulphuric acid of from 90 to 95%, H SO content, under a pressure. in

excess of 250 pounds per square inch and at a temperature of from 30 to 95 C.

8. Process of sulphating ethylene, which comprises contacting ethylene in gas phase with aqueous sulphuric acid of from 85 to 190%, H SO content, under a pressure in excess of 250 pounds per square inch and at a temperature of from 80 to 100 C.

9. Process of sulphating ethylene, which comprises contacting ethylene in gas phase wth aqueous sulphuric acid of from 80 to 85%, H SO, content, under a pressure in excess of 250 pounds per square inch and at a temperature of from 100 to 125 C.

10. Process of sulphating ethylene, which comprises contacting ethylene in gas phase with aqueous sulphuric acid of from 90 to 90%, HgSO4 content, under a pressure in excess of 500 pounds per square inch and at a vtemperature of from to 85 C.

11. Process of sulphating ethylene, which I comprises contacting ethylene in gas phase with aqueous sulphuric acid of from 80 to -90%, H SO content, under a pressure in- 13. Process of sulphating ethylene which comprises contacting ethylene in as phase with aqueous sulphuric acid of a ut 80% H 80, content, under a pressure in excess of 250 pounds per square inch and at a temper-- ature of from 100 to-125 C.

14. Process of sulphating ethylene which comprises contacting ethylene with acqueous sulphuric acid of from 80 to 90%, H SO, content, under a pressure in excess of 250 pounds per square inch and at a temperature of from 30 to 125 C. I

' BENJAMIN T. BROOKS. 

